Am I not able to access phone #s on the trial plan?

Yes, phone number enrichments are not available during the trial period. Our 14-day free trial includes 1,000 credits and gives you access to many Pro features like webhooks, CRM integrations (HubSpot, Salesforce), email sequencers, and HTTP API capabilities, but phone number enrichments are specifically excluded. To enable phone number enrichments, you'll need to upgrade to a paid plan after your trial ends.

Source: Workspace administration documentation | Documentation | Clay University